Segmental spinal reflex adaptations associated with chronic ankle instability.
OBJECTIVE
To further understanding of the role that segmental spinal reflexes play in chronic ankle instability (CAI).


METHODS
A 2 x 2 repeated-measures case-control factorial design. The independent variables were ankle group with 2 levels (healthy, CAI) and stance with 2 levels (single, double legged).


METHODS
University research laboratory.


METHODS
Twenty-two participants with CAI and 21 matched healthy controls volunteered.


METHODS
Not applicable.


METHODS
The dependent variables were 2 measures of motoneuron pool excitability: paired reflex depression (PRD) and recurrent inhibition.


RESULTS
A 2 x 2 repeated-measures multivariate analysis of variance revealed a significant interaction between group and stance on the linear combination of PRD and recurrent inhibition variables (Wilks lambda=.808, F(2,40)=4.77, P=.014). Follow-up univariate F tests revealed an interaction between group and stance on the PRD (F(1,41)=9.74, P=.003). Follow-up dependent t tests revealed a significant difference between single- and double-legged PRD in the healthy participants (t(20)=-3.76, P=.001) with no difference in CAI participants (t(21)=-0.44, P=.67). Finally, there was a significant difference in recurrent inhibition between healthy (mean, 83.66) and CAI (mean, 90.27) (P=.004).


CONCLUSIONS
This study revealed that, compared with healthy participants, CAI participants were less able to modulate PRD when going from a double- to a single-legged stance. Additionally, CAI participants showed higher overall levels of recurrent inhibition when compared with healthy matched controls.
Sefton
JoEllen M
JM
Department of Kinesiology, Auburn University, Auburn, AL 36849-5323, USA. jmsefton@auburn.edu
Hicks-Little
Charlie A
CA
Hubbard
Tricia J
TJ
Clemens
Mark G
MG
Yengo
Christopher M
CM
Koceja
David M
DM
Cordova
Mitchell L
ML
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000704:Analysis of Variance; D000842:Ankle / Q000294:innervation / Q000502:physiology*; D016512:Ankle Injuries / Q000503:physiopathology*; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology